Abstract: The growth characteristics of fish not only reflect their growth and survival, but also to some extent the quality of their living environment and life history. In this study, three released fish species（Hemibarbus labeo, Leuciscus waleckii and Phoxinus lagowskii）were captured in the lower Yalu River from November 2020 to October 2021. Their biological parameters and growth characteristics were analyzed, and mortality coefficients, exploitation rates were estimated by FiSAT II software. The results showed that the dominant age compositions of Hemibarbus labeo, Leuciscus waleckii and Phoxinus lagowskii were 1 a, 1 a-2 a, 1 a, respectively. The b were all similar to 3（P>0.05）, which is a uniform growth type; the growth coefficient K was greater than 0.2, which is a fast-growing type. The growth performance indexφ′ was between 4.46-5.00, the inflection point ages of Hemibarbus labeo, Leuciscus waleckii and Phoxinus lagowskii were 2.33 a, 1.95 a and 1.05 a, respectively, and the corresponding body lengths at inflection point were 318.52 mm, 255.67 mm and 115.52 mm, respectively. The exploitation rate E was greater than E_max, indicating that they were overexploited, so their fishing should be restricted. The optimal body lengths for the fishing of Hemibarbus labeo, Leuciscus waleckii and Phoxinus lagowskii should be 319 mm, 256 mm and 116 mm. The investigated waters should maintain the resources with measures of increasing and releasing fish, adjusting the number of fish that have been increased and released, and appropriately increasing the resources of Hemibarbus labeo, Leuciscus waleckii and Phoxinus lagowskii so as to promote resource utilization and sustainable development.

Key words: Lower Yalu River, age, growth parameters, population parameters